Based on the evidence presented in the course of this book, I argued in the last chapter that Ivo did not compile the Panormia, the great legal collection that was attributed to him from the twelfth century onwards and that has commonly been seen as his masterpiece. There is still a large body of legal works that can be attributed to Ivo with certainty, namely the Decretum, the Prologue introducing it, and a large number of letters. Yet while all these works are related to each other in many different ways – by textual interdependence, by common forms of argument, and so on – there is no such link between these genuine works of Ivo and the Panormia to justify the assumption of a common authorship. In particular, Ivo shows no acquaintance with the Panormia or with any of its distinctive sources, just as the Panormia compiler does not draw independently on any of the sources underlying Ivo's works. This negative evidence can be further supported by positive evidence from the structure of the Panormia: the concepts governing the selection and the arrangement of the material diff er profoundly from those of the genuine works of Ivo.

The only reason why a collection so different from the Decretum and Ivo's other works soon came to be regarded as his work is that the Prologue introducing the Panormia mentions Ivo as the author. All medieval authorities calling the Panormia Ivonian – copies of the Panormia, library catalogues, literary histories – in this respect depend on the transmission of Ivo's Prologue with the Panormia.